Salt spray test

Salt Spray Test

Salt Spray Testing is a widely used accelerated corrosion test used to evaluate the ability of coatings to resist corrosion or to compare the relative performance of different coatings. During a salt spray test a sample is exposed to a salt/water solution that is sprayed onto the sample with a nebulizer. The salt solution forms a corrosive environment that accelerates the corrosion of of the sample. The corrosion rate can then be evaluated by comparing the amount of corrosion on the sample compared to a standard or control sample.

Salt Spray testing involves exposing a test sample to an atomized salt/water solution. The aerosol is generated by a nebulizer which breaks up the solution into fine mist particles. The sample can be fully or partially immersed in the aerosol. The test typically involves exposing the sample to 95% relative humidity and a temperature range of 35 to 46 degrees Celsius.

The sample should remain in the Salt Spray chamber for a defined period of time and then removed and visually inspected. In some ways Salt Spray Testing has been made redundant due to the consistent methodology and accelerated timeframes used in modern laboratory tests. The use of temperature and humidity chambers have also reduced the need for Salt Spray Testing.

Despite this, Salt Spray Testing is still an important tool for investigation into corrosion resistance of coatings. It is often used to evaluate the performance of similar coatings or to compare coatings from different manufactures. It can also used to assess the effect of sacrificial and barrier coatings, plating and other surface treatments used for corrosion resistance.

Salt Spray Testing is a complex and intricate process as the procedure required for the test can vary depending on the material, coating and application requirements. It is important to note that when interpreting the results it is important to take into account the specifics of the individual sample and the relevant test parameters.

Salt Spray Testing is not a standardized test and there are different standards or protocols used by many laboratories. This means that it is important to communicate the tested standard and desired outcome clearly with the laboratory to ensure consistent results.

It is also important to note that once the sample is removed and examined visually it can be difficult to determine whether the corrosion was caused by an inadequate coating or the Salt Spray Test itself. This is why Salt Spray Testing is typically preceded by other tests such as chemical, mechanical and environmental resistance tests.

All in all Salt Spray Testing can be an effective tool to evaluate relative performance of different coating and to identify weaknesses in a coating’s ability to resist corrosion. It is important to use the test in conjunction with other types of tests and to take into account the specific requirements of the sample and the test.